Allanite is one of the most common rare earth minerals. The International Mineralogical Association has listed 3 minerals in the allanite group, namely allanite (Ce), allanite (La) and allianite (Y), depending on the dominant rare earth present, cerium, lantharium or yttrium. Also called Orthite, it occurs mainly in metamorphosed clay rich sediments and igneous rocks. It is usually black in color, but can also be brown and brown-violet. It is found in many places, including California, New Jersey and New York in the US. Allanite crystals are commonly opaque and vitreous to greasy in luster. A 12-ounce Allanite crystal specimen costs about $30 and the prices may vary depending on the product name, color and size.